Ubuntu

Why are these ports open and are they safe and who are they open too???

Asked by Mark

When I scan my routers static IP adress using gnome-nettol, I get a list of open ports. These are the open ports that it shows open::

Port: State: Service:
21 open ftp
23 open telnet
53 open domain
80 open www
1863 open msnp
1864 open unknown
4443 open unknown
5190 open aol
5431 open unknown
5566 open unknown
30005 open unknown

I am relatively new to using ubuntu and I must admit I am a little worried from a security point of view, because of these open ports.
If at all possible, I would like to know why these ports are open? who are these ports open too? and are thay safe to be open and how can I close and open ports manually??

I am using a Sagem f@st 2504 SKY router and I have searched for an manual to see if i can stop my router accepting PING requests with no luck as of yet.

Cheers for now

Mark Hogan...

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Joerg Hahn (hahnjoerg) said : 		#1

Hello Mark

I can not tell a thing about this router. But I found an English description for the port numbers and applets they normally use them. You can find it here:
http://meineipadresse.de/html/ip-ports.php

An open port are nothing to worry about in first sight. If there is no applet listening on this ports, nothing can happen. You can find out, which program is listening on which port by asking netstat (http://linux.die.net/man/8/netstat). Type netstat -pal and you will see, which program uses which port and if it is listening. If you add a "n", then you can see better the port it listening on. As I said: no program on the port => nothing to worry about.
To close a port, you have to read more about the firewall and its administration. There is the point you can close or open a port.

yours george

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Mark (mark-j-hogan) said : 		#2

Thanks George That was just the answer I was looking for..

Cheers pall
Kind Regards

Mark Hogan...